.TH std::flat_map::extract 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::flat_map::extract \- std::flat_map::extract

.SH Synopsis
   containers extract() &&;  (since C++23)

   Extracts adapted containers c. Equivalent to return std::move(c);.

   After this operation *this is empty, even if an exception is thrown.

.SH Parameters

   \fI(none)\fP

.SH Return value

   std::move(c).

.SH Complexity

   Constant.

.SH Example


// Run this code

 #include <cassert>
 #include <flat_map>
 #include <print>
 #include <type_traits>
 #include <vector>

 int main()
 {
     std::flat_map<int, double> map{{1, 1.1}, {2, 2.2}, {3, 3.3}};
     const auto size = map.size();

     auto c = map.extract();
     assert(c.keys.size() == size);
     assert(c.values.size() == size);
     assert(map.empty());
     assert(map.keys().empty());
     assert(map.values().empty());

     // The default keys and values containers are std::vector:
     static_assert(std::is_same_v<decltype(c.keys), std::vector<int>>);
     static_assert(std::is_same_v<decltype(c.value), std::vector<int>>);

     std::println("keys: {}", c.keys);
     std::println("values: {}", c.values);
 }

.SH Output:

 keys: [1, 2, 3]
 values: [1.1, 2.2, 3.3]

.SH See also

   replace replaces the underlying containers
           \fI(public member function)\fP
